The present invention relates to devices and systems of such devices for monitoring and/or affecting parameters of a patient's body for the purpose of medical diagnosis and/or treatment. More particularly, systems in accordance with the invention are characterized by a plurality of devices, preferably battery powered, configured for implanting within a patient's body, each device being configured to sense a body parameter, e.g., temperature, O2 content, physical position, electrical potential, etc., and/or to affect a parameter, e.g., via nerve and/or muscle stimulation.
Commonly owned U.S. Pat. Nos. 6,164,284, 6,208,894, and 6,315,721, each entitled “System of lmplantable Devices For Monitoring and/or Affecting Body Parameters” and U.S. Pat. No. 6,185,452 entitled “Battery Powered Patient Implantable Device”, each incorporated herein by reference in their entirety, describe devices configured for implantation within a patient's body, i.e., beneath a patient's skin, for performing various functions including: (1) stimulation of body tissue and/or sensing of body parameters, and (2) communicating between implanted devices and devices external to a patient's body. Such implantable devices are preferably powered using rechargeable batteries and are programmed, e.g., via a programmer external to the patient's body. Once programmed, such devices are capable of operating “independently” according to their programmed parameters. However, it is not always convenient to use an external programmer due to cost, size, or availability constraints. Accordingly, a commonly assigned U.S. patent application Ser. No. 10/080,881 entitled “Magnet Control System For Battery Powered Living Tissue Stimulators” has been concurrently filed with this patent application, said application being incorporated by reference in its entirety herein. This copending patent application addresses this need by describing a programming system that can use a readily available, low cost, magnetic means or variations thereof, to program such implantable devices. It is also valuable to be able to selectively pause/stop the operation of such an implanted device, e.g., see U.S. Pat. No. 6,101,417 to Vogel et al. which describes the capability to protect the operation of an implanted device from being evoked by an unexpectedly large magnetic field, e.g., resuitbig from an MRI device. The present invention improves upon such a capability by using an interlocking magnetic device, e.g., an electromagnet, that generates a string of magnetic pulses to evoke (or suppress) a response in the implantable device. By distinguishing the amplitude/duration/sequence of magnetic pulses, implanted devices can be selectively activated or deactivated.